Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona

By Jeanne E. Klawon

Arizona Geological Survey Open-File Report 00-02

March, 2000

Arizona Geological Survey 416 W. Congress, Suite #100, Tucson, Arizona 85701

46 p. text

Investigations supported by the Arizona State Land Department As part of their efforts to gather technical information for stream navigability assessments Investigations done in cooperation with JE Fuller Hydrology / Geomorphology

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 1 EXECUTIVE SUMMARY

This report provides hydrologic and geomor- than 10 cfs. Flood events are dramatic in phologic information to aid in the evaluation of comparison. Historical peak flow estimates for the navigability of the Big Sandy River, Santa these rivers have been estimated at 68,700 Maria River, and Burro Creek. These streams cubic feet per second (cfs) (2/9/93) for the Big flow through rugged mountainous terrain of Sandy River, 47,400 cfs (2/14/80) for Burro Mohave, Yavapai, and La Paz counties in Creek, and 23,100 cfs (3/1/78) for the Santa western Arizona and join to form the Bill Maria River. The largest flow events have Williams River at what is now Alamo Dam occurred during the winter months when and Reservoir. The rivers reflect a diversity of meteorological conditions cause a series of channel patterns, and include the mainly wide storms to pass through the region, frequently and braided sandy alluvial channels of the Big generating multiple floods within a given year. Sandy River, the narrow bouldery channels in All three rivers in many cases record the same bedrock canyons of Burro Creek, and a mix of flood events, reflecting the regional extent of bedrock canyons and wide alluvial channels on the storms. the Santa Maria River. Substantial channel changes have oc- Although none of these tributaries has an curred along the alluvial reaches of these rivers abundant water supply, the relative surface- in the past 100 years. Most channel changes water flow of each river does vary. For most of have occurred during large floods. Channel its length, Burro Creek contains water that changes typically have involved erosion of flows year round or is relegated to discontinu- stream terraces and tributary fans around ous pools during the dry portions of the year. outside bends, removal of vegetation within The Big Sandy River maintains perennial flow the channel, and in some cases, channel widen- along some portions of its length and is fed by ing. Analysis of channel change spans the 20th upper watershed perennial streams such as century. Based on historical accounts, dramatic Trout Creek. The Santa Maria is the driest of channel changes occurred around the turn of all three rivers, with most of its surface-water the century; based on interpretation of aerial flow produced by tributaries in the upper photographs of the rivers, dramatic channel watershed and in the main channel for 10-15 changes also occurred during floods from 1978 miles near its mouth. Low flow discharge to 1995. measurements of each river are generally less

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 2 INTRODUCTION

This report summarizes the geomorphology some detail in order to understand the meteo- and hydrology of the three principal tributary rology and hydrology of the largest flows in streams of the Bill Williams River in western the gage record. Pre-gage historical documents Arizona. The Bill Williams River basin drains and paleoflood records provide additional most of west-central Arizona, straddling information on the hydrologic behavior of the Mohave, Yavapai and La Paz counties (Figure Bill Williams River basin. Following the 1). The principal tributaries of the Bill Will- hydrologic discussions, channel characteristics iams are Big Sandy River, which heads east of are described as well as channel changes that Kingman, and Santa Maria River, which heads may have occurred within the last century. near Hillside. These tributaries join to form the Because of the extensive length of each river, Bill Williams River at what is now Alamo specific reaches were selected and studied Lake. Burro Creek is the largest tributary of using aerial photographs, topographic maps, Big Sandy River, entering south of Wikieup. and general land office surveys from the early The rugged terrain of the Bill Williams 1900’s. Appendices include a list of contacts, River basin has limited human habitation to a rating curves for primary stream gages, and few small towns and land development to photo documentation of river reaches. irrigation agriculture and ranching mainly in the Big Sandy Valley and along the Bill Will- iams. Although the area was host to many Acknowledgments mines which sought gold, silver, copper, and Kyle House and Pat Shafroth provided infor- other associated minerals, the rugged terrain mation and feedback that facilitated prepara- and limited water resources in the area im- tion of this report. Phil Pearthree reviewed and peded the development of large-scale enter- edited the report. Pearthree and Tim Orr helped prises. A notable exception is the Bagdad prepare figures for inclusion in this report. Pete copper mine in the Santa Maria River drainage Corrao is responsible for final layout of the basin. Thus, for the most part, this area re- text and illustrations. mains a remote location in Arizona. Geologic Setting Purpose and Scope The Bill Williams River basin is located in the This section provides hydrologic and geologic Basin and Range and Transition Zone geologic information to aid in the determination of provinces in west-central Arizona. The Basin navigable versus non-navigable status for the and Range province extends from the Snake major tributaries of the Bill Williams River in River Plain in Idaho through southern Arizona western Arizona. It begins with a brief intro- and into Mexico. The Basin and Range prov- duction to the geology, climate, and physiogra- ince is characterized by generally north- phy of the region. Hydrologic information is trending mountain ranges (Spencer and the focus of the paragraphs which follow Reynolds, 1989) which are separated by basins introductory information and includes the formed by normal faulting along mountain history of stream gages within the basin and fronts. In southern and western Arizona, basins analysis of their surface water records. Se- are deep, well-defined grabens which trend lected floods from this century are discussed in north to northeast, and have fairly regular

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 3 Figure 1. Location of the Big Sandy and Santa Maria rivers and Burro Creek in western Arizona.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 4 spacings of 25 to 50 km (Menges and diate volcanism to predominantly basaltic Pearthree, 1989). The Big Sandy Valley is the volcanism. most prominent basin in the study area and is Sediments that filled the structural basins composed of basin fill over 3000 ft in depth formed by regional extension can be grouped (Davidson, 1973). The Transition Zone is the into upper and lower basin fill, and Quaternary rugged, mountainous country between the deposits. Lower basin fill ranges in age from Basin and Range and the Colorado Plateau. It middle to late Miocene, was deposited as has geologic and physiographic characteristics normal faulting continued, and has a thickness that are transitional between the highly de- of at least 3,000 ft in the Big Sandy Valley. formed Basin and Range and the relatively Upper basin fill is as much as 300 ft thick and undeformed, fairly high Colorado Plateau to was deposited in the waning stages of defor- the northeast. mation during the Pliocene and early Quater- The geology of the Bill Williams River nary. Pedimentation along mountain fronts was basin reflects the complex history of the Basin begun in this period and continued into the and Range province, with several periods of middle Quaternary along with the deposition of magmatism and overprinting of compressional thin coarse-grained fans. Through the Quater- and extensional terranes in the past 80 million nary, alluvial fans and terraces have been years. A period of wide-reaching magmatism deposited, modified, and eroded through and crustal shortening associated with the processes which are for the most part driven by Laramide orogeny occurred in middle to late climate changes. The oldest and highest allu- Cretaceous to early Tertiary period, about 80 to vial fans in the Big Sandy Valley occur in the 60 million years ago. This same area was upper watershed of Tule Wash and are about extended in the middle Tertiary between about 200 ft thick. The bedrock mountains and 20 and 10 million years ago, forming major alluvial basins have continued to be dissected low-angle normal faults trending east-north- during the Pliocene and Quaternary as regional east-west-southwest. Large amounts of exten- drainage systems have continued to downcut. sion occurred in the area south and west of the Sediments from coalescing drainages, depos- Big Sandy - Santa Maria confluence, resulting ited in the floodplains and streams of the study in the exposure of rocks in the Buckskin, area, usually amount to no more than 40 ft in Rawhide, and Harquavar mountains that were thickness (Menges and Pearthree, 1989; buried beneath many miles of rock prior to the Davidson, 1973). period of extension. Lesser amounts of middle Tertiary extension occurred in the Transition Zone to the northeast. As a result of this Physiography extension, the region experienced a reversal of Most of the Bill Williams River basin is in the surface drainage direction from north-flowing Basin and Range province and the rugged to south-flowing streams as the extended part Transition Zone along the margin of the high of the crust subsided. Relatively modest late elevation Colorado Plateau (Figure 2). The Big Tertiary extension in an east-west to east- Sandy River basin has a total relief of 7297 ft southeast-west-northwest direction was accom- and an area of ~2810 mi2 (House, 1997), which modated by higher-angle normal faults includes 687 mi2 (Markman, 1996) of the (Zoback and others, 1981). The change in Burro Creek watershed. The Big Sandy River extension direction and style in the late Ter- begins at the confluence of Knight and Trout tiary was accompanied by magmatic composi- creeks in the Pilgrim Wash Quadrangle and tion changes from primarily silicic to interme- flows south through Big Sandy Valley, then

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 5 Figure 2. USGS 7.5’ topographic quadrangles covering the study area and active stream gages. These tributaries of the Bill Williams River flow south to the confluence of the Big Sandy and Santa Maria rivers, where they combine to form the Bill Williams River.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 6 cuts through the mountainous terrain of Green- semi-arid to arid. Temperature and precipita- wood Peak, Signal Mountain, Arrastra Moun- tion values as well as dominant vegetation vary tain, and Artillery Peak to its mouth, where it substantially within the basin, with pinyon- converges with the Santa Maria River. It has a juniper woodlands in the mountain ranges and main channel gradient of 0.008 (Garrett and cacti and riparian species in the intervening Gellenbeck, 1991) above the gaging station 17 valleys. Average January temperatures range miles south of Wikieup; other calculated from 35° to 45° F at higher elevations to 45°- gradients include 0.011 north of Cane Springs 50° F at lower elevations. Average July tem- Wash and 0.006 in the southern portion of Big peratures range from 65°-75° F at higher Sandy Valley (Davidson, 1973). Burro Creek elevations to 80°-90° F at lower elevations in heads in western Yavapai county between the the watershed (Sellers and Hill, 1974). Mohon and Santa Maria Mountains near the Precipitation also varies considerably Luis Maria Baca Float No. 5, flows southwest within the Bill Williams River basin. Annual through Bozarth Mesa and the rugged terrain precipitation is generally between 10 and 15 of the Poachie Range, and joins the Big Sandy inches for valleys and low elevations, dropping River approximately 12 miles south of as low as 6 inches near the mouth of Bill Wikieup. Total relief from its source to its Williams River (United States Army, Office of mouth is 5979 ft. Selected stream reaches the Chief Engineer, 1944), and 15-20 inches in located below the confluence with Boulder the mountainous high-elevation areas (Sellers Creek and an 11-mile-long stretch that begins and Hill, 1974). 15 miles above the confluence with the Big Precipitation falls mainly in summer and Sandy River, have gradients of 0.006 winter rainy seasons. Summer rains occur (Markman, 1996). The Santa Maria River primarily during the afternoons and evenings heads in the Santa Maria Mountains near the in July and August and also in some valleys Luis Maria Baca Float No. 5 and has a water- between 6 and 9 am. Summer storms are for shed area of 1520 mi2 (House, 1997). It has a the most part generated by convection, in gradient of 0.009 above the gaging station near which moisture from the Pacific Ocean and the Bagdad and a lower gradient of 0.008 (Garrett Gulf of Mexico encounters heated mountain- and Gellenbeck, 1991) upstream from the ous terrain, which causes the air to increase in gaging station near Alamo, which includes a temperature and rise. These unstable air masses gradual alluvial reach downstream from the lead to high intensity rainstorms of short Bagdad gage. From its source, the drainage duration often accompanied by thunder, light- flows to the southwest past Grayback Moun- ning, and strong winds (Sellers and Hill, 1974). tain and Ives Peak and turns to the west to Dissipating tropical storms from the meet the Big Sandy River near Alamo. With eastern Pacific occasionally bring heavy the highest elevation in the watershed at 7626 precipitation to portions of western Arizona ft in the headwaters of Kirkland Creek during the late summer and early fall. For these subbasin, and the lowest on the order of 1120 storms to cross Arizona, the jet stream is ft at its confluence with the Big Sandy, the rerouted to the northeast and commonly inter- Santa Maria River watershed has a total relief acts with a cutoff low or low pressure trough of 6506 ft. (House, 1997). The largest floods recorded at the Santa Maria River gage near Alamo oc- curred in the late summer and early fall during Climate the 1939, 1951 and 1964 water years. In his The climate of the Bill Williams River basin is investigations in western Arizona, House

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 7 (1997) found that large late summer and early storms result from the westward displacement fall floods occurred in 1939 and 1951, as well of the ridge of high pressure in the Pacific as 1970 and 1976. It is not possible to know if Ocean and the formation of a semi-permanent the gage on the Santa Maria River near Alamo low-pressure trough over the western United also experienced large floods during 1970 and States. In this situation, storms tend to move 1976 as it was discontinued in 1966. south along the west coast instead of through In the upper Bill Williams River basin, Washington and Oregon. They then travel east stream gages have recorded high peak flows in from the coast through California and Arizona. the late summer-early fall months that presum- Usually this storm track may produce precipi- ably resulted from dissipating tropical storm tation in Arizona for a couple of days and precipitation events. Their magnitudes are continue to the east; this pattern tends to recur smaller in comparison to winter flood events at and may produce several precipitation events the same gages, however. The largest flood of within a short time interval. However, if the this type was 15,200 cfs recorded at the Santa high-pressure system in the north becomes Maria River gage near Bagdad on September especially well developed, the low pressure 24, 1983; this discharge is among the top ten cell tends to become isolated from the track largest floods recorded at this gage. Large and may stagnate and intensify off the coast. flows were also recorded on this date at Burro By the time the storm reaches Arizona, it is Creek (11,900 cfs) and Big Sandy River near fully developed and capable of producing Wikieup (12,900 cfs). large-magnitude events. In fact, when the flood Although winter rains are generally records of large drainages of western and lighter and longer lasting than summer rains, central Arizona are analyzed, it is almost unusual meteorological phenomena may bring always the case that the largest floods on abundant precipitation across the Bill Williams record have occurred during the winter season River basin during the winter months. These (House and Hirschboeck, 1997).

HYDROLOGY

This subsection summarizes various aspects of lengths (Figure 3). In this report, a reach is the hydrology of the Big Sandy and Santa perennial if it usually flows year round; how- Maria rivers and Burro Creek. I briefly discuss ever, some reaches included in the perennial reaches with perennial flow on each of these category run dry during periods of extreme streams, summarize historical flow records, drought (Brown, et al, 1978). Reaches that are and discuss in more detail the genesis of a few termed perennial by Brown et al (1978) and of the largest floods that have occurred in this Freethey and Anderson (1986) are described as drainage system. having a base flow of less than 10 cfs. In its headwaters, the Big Sandy River is supplied by perennial reaches of Willow Creek and the Areas of Perennial Flow Trout Creek basin. The main stem perennial The Big Sandy, Santa Maria Rivers, and Burro reaches stretch from Wikieup downstream to Creek all have perennial reaches along their the Burro Creek confluence and from Signal to

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 8 Figure 3. Perennial stream reaches in the upper Bill Williams River basin (data from Brown, et al., 1978, and Freethey and Anderson, 1986).

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 9 Figure 4. Active and discontinued stream gages in the Bill Williams River basin. Discontinued gages typically have short records from the 1960’s and 1970’s. Exceptions are of the gage on Burro Creek, which records flow through the 1980’s, and the Santa Maria gage near Alamo, which began in 1939 and was discontinued when Alamo Dam was completed and a new gaging station was established upstream.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 10 Table 1. List of stream gages of the Bill Williams River Basin above Alamo Dam.

Alamo Lake. The Whipple expedition, which headwater tributaries of Cottonwood, Smith, traveled through this area during 1853 and and Sycamore creeks. The main stem Santa 1854, described the Big Sandy as having a Maria is perennial approximately 5 miles water source which sinks and rises in the sandy above and below Bridle Creek, and 5 to 10 channel along the length of the river (Foreman, miles upstream from Alamo Lake. Portions of 1941). Perennial flow in the Wikieup reach Kirkland Creek and Date Creek also flow year averaged 2.52 cfs from 21 miscellaneous round. measurements taken between 1959 and 1964 (Davidson, 1973). Burro Creek is perennial along most of its length with the exception of Surface Water Records the reach near U.S. Route 93 bridge crossing. Gage History. Stream flow volumes were first Tributaries of Burro Creek that are perennial recorded in 1939 in the Bill Williams River include sections of Francis Creek, Boulder basin, beginning with stream gages on the Bill Creek, and Pine Creek. The reaches in these Williams River and Santa Maria River near tributaries are all located within the first five Alamo, Arizona (Figure 4; Table 1). These miles upstream of the river mouth. The Santa gages evolved as Alamo Dam near Alamo, AZ Maria River basin has perennial reaches in the was proposed and built, and Alamo Lake

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 11 developed behind it. The gage near Alamo on Many of these properties were washed away the Santa Maria was discontinued in 1966 during floods in the 1880’s and early 1900’s. because it was within the area of Alamo Lake; Cofer describes her experience of one of these it was replaced by a new gage located about 10 floods on New Year’s Eve, 1908: miles upstream (Santa Maria near Bagdad “The first really big flood that I saw in the gage). The USGS first began measuring Sandy River; one that cleaned the trees and streamflow on the Big Sandy River and Burro brush from the river bottom and took cotton- Creek in 1966 and 1980, respectively, but they wood trees from the banks that were perhaps a discontinued the Burro Creek station following hundred years old and tossed them end over the 1993 water year. Stream gages were also end like they were two by fours.” [Cofer installed on a number of tributaries to the Big 1969:76] Sandy, Santa Maria and Burro Creek; however, Paleoflood Records. Paleoflood hydrol- these gages were short-lived and mainly record ogy is an interdisciplinary approach used to stream flow from the early 1960’s to the late study historic and prehistoric records of floods 1970’s. Active stations in the Bill Williams in river systems around the globe and is appli- River basin upstream from Alamo Dam in- cable to a wide range of scientific topics and clude the Big Sandy River near Wikieup, AZ, practical problems. By extending the flood Santa Maria River near Bagdad, AZ, and the record beyond a relatively short historical data Bill Williams River below Alamo Dam. set, geologists are able to extract more repre- Pre-gage Flood Records. Gage records sentative samples of the largest floods for give a picture of the past 60 years, at best; flood frequency analysis and to address long- other accounts of pre-gage late 19th century to term issues such as aggradation and degrada- early 20th century flooding suggest that this tion in the fluvial system, as well as flood- was a wet period with many floods, some of climate linkages for a particular region. The which probably exceeded the floods in the method produces results that are very useful gage record. Years that have been noted to and needed in urban planning, flood control have large floods on the Bill Williams River procedures, and reservoir operation (Stedinger include 1884, 1891, 1905, 1906, 1910, 1911, and Cohn, 1986; Hereford, et al., 1996; Graf, et 1915, 1916, 1920, 1923, 1927, 1930, 1931, al., 1991; Patton, 1977; Costa, 1978; Macklin, 1932, 1937, 1938, and 1939. Although the et al., 1992). magnitudes of these most of these floods are The slackwater deposit-paleostage indica- not known, indirect estimates were made for tor (SWD-PSI ) technique in paleoflood hy- the largest of these, which include the flood of drology allows for indirect discharge measure- February 1891 estimated at 200,000 cfs and ments following a flood by using features January 1916 at 185,000 cfs. This is in contrast which record the height of the flood waters to the largest recorded discharge measurement (Baker, 1987; Kochel and Baker, 1982; Patton, of 92,500 cfs which was made on February 7, et al., 1979). Slackwater deposits are fine- 1937 at the Bill Williams River near Alamo grained deposits, typically composed of silt (United States Army, Office of the Chief and sand, which accumulate in backwater Engineer, 1944). Historic accounts of this zones where reduced velocities allow fine period by Irene Cornwall Cofer who lived in particles to fall from suspension. Reaches most the Big Sandy Valley at the turn of the century conducive for preserving slackwater deposits relate that prior to the 1880’s, the Big Sandy include those that have fixed channel bound- River channel was narrow, allowing for wide aries and features which initiate flow separa- agricultural fields, orchards, and ranch houses. tion, such as alcoves, channel constrictions,

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 12 minor tributary mouths, or bedrock obstruc- high flow for periods of days. The driest tions. Paleostage indicators include all other periods for these rivers occur during early high water marks such as flotsam piles and summer (June and July) and late fall (October mats, scour lines, non-exceedance indicators, and November), in which flow may cease or water stains on trees and bedrock, and tree drop to a few cfs. scars. The three rivers in this study exhibit The Bill Williams River basin has not records of daily flow values that differ in been extensively studied from a paleoflood magnitude and seasonal variability according perspective, although a paleoflood project is to the hydrologic characteristics of each river. currently underway in this basin (House, oral The Big Sandy River near Wikieup, supported communication, 1998). Ely (1992) studied by a shallow aquifer in the Big Sandy Valley selected paleoflood sites along the Bill Will- alluvium as well as several springs in the area, iams River, Big Sandy River and Burro Creek continues to flow year round. Daily flow in order to extract regional information about values are generally less than 10 cfs during the variations in large-flood frequency in Arizona drier months; wetter months have slightly and southern Utah within the past 5000 years higher daily flow values and sharp flood peaks and their relation to long-term meteorological during storms. No flow days (i.e., days which patterns and other paleoclimatic indicators. no flow is recorded) have not occurred at this Ely’s Big Sandy River paleoflood site is particular gage, meaning that this reach of the located 9 miles downstream from the Big Sandy River is consistently perennial. confluence with Burro Creek at 34°27’14” N, Burro Creek experienced sustained flow for 113°37’33” W, and is composed of 3 inset most of the gage period of 1984-1993, al- stacks of deposits, the highest of which is though many times flow was less than 1 cfs covered by mesquite trees. Although a radio- during the dry months of the year. During carbon date from this uppermost deposit some years, however, especially in the late suggests that the entire package of floods is 1980’s and early 1990’s, no flow days were relatively young, the lack of flood evidence on recorded. These totaled 388 out of 4922 days the top surface indicates that the highest extent in the gage record; in other words, approxi- of deposits had not been overtopped in the mately 8% of the total gage record measured historic period prior to 1992 and thus that mean daily flow values of 0 cfs. The Santa larger floods than those measured historically Maria at the gage near Bagdad has experienced have occurred. Ely’s paleoflood site at Burro seasonal variability similar to the Big Sandy Creek near Andy’s Hole (34°32’43” N, River and Burro Creek, but there is a greater 113°29’14” W) is similarly young, with 5 or 6 difference in magnitude between high flow flood deposits preserved. periods and low flow periods during the year. For example, 7,112 of 10,393 or 68% of daily flow values have been no flow days on the Hydrologic data Santa Maria River. Thus, the Santa Maria Mean daily flow series. The magnitudes of River in its upper reaches is more sensitive to mean daily flow values fluctuate seasonally fluctuations in precipitation, whereas the other and annually on rivers in the Bill Williams gage locations discussed above have alternate River basin. The largest flow volumes occur ground water sources that sustain flow during during the winter (December through March) the drier portions of the year. and early fall (August though September) and The Santa Maria River near Alamo, arrive in the form of floods as well as sustained located near the river’s mouth, had a strikingly

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 13 Figure 5. Mean annual flow at the USGS stream gage on Big Sandy River near Wikieup, Arizona.

Figure 6. Mean annual flow at the USGS stream gage on Burro Creek at Old U.S. 93 Bridge.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 14 different record than the gage upstream. Only Mean annual flow series. The mean annual 1.6% of the gage near Alamo record is com- flow series, the arithmetic average of mean posed of no flow days compared to 68% at the daily flow values for each year in the period of gage near Bagdad. While this gage does record record, is best used to identify high flow and a completely separate time interval than the low flow years on record for a given gage. The upstream gage, the difference in records is Big Sandy River near Wikieup experienced its almost certainly due to the change of location record high flow year in 1993, which includes on the river rather than a change in the overall the flood of record (68,700 cfs, 2/9/93) and a hydrology of the system. The larger drainage number of other large flood peaks during the area above the gage near Alamo may contrib- winter of 1992-93 (Figure 5). The record low ute to the larger peak discharge values re- flow year for the gage was in 1996, when its corded there. The maximum peak discharge largest flow value amounted to 275 cfs on 9/9/ recorded near Alamo (August 29, 1951) is 96. For Burro Creek, the record high flow year approximately 10,000 cfs greater than any peak was again 1993 with the flood of record esti- discharge recorded more recently at the up- mated at 55,300 cfs on February 8, 1993 stream gage. The two gage records also differ (Figure 6). The record low flow year for Burro markedly in the seasonality of the largest Creek was 1987, which had a peak discharge floods. The largest floods at Alamo (1939-65) of 565 cfs on 3/5/87. The Big Sandy gage also occurred during the late summer-early fall, recorded a low flow year in 1987. On the Santa while those floods which dominate the Bagdad Maria River, the record low flow year occurred record (1966-present) occurred during the in 1956 at the Santa Maria River near Alamo, winter months. Based on the time of year in in which mean annual discharge measured 2 which they occurred, the late summer-early fall cfs and the peak flow value measured 107 cfs floods were generated by summer monsoonal (Figure 7). The record high flow year occurred storms or dissipating tropical storms. Hydro- in 1941, in which multiple flood peaks through logic data for the Santa Cruz River in southern the winter contributed to a high mean dis- Arizona exhibit a somewhat similar trend charge for the given water year. The largest (Webb and Betancourt, 1992). From 1930-59, peak of this year measured 20,600 cfs on 3/14/ the Santa Cruz flood record is dominated by 41. The Santa Maria River near Bagdad summer monsoonal floods, none of which experienced comparable high flow years in were very large, while the record from 1960-86 1979 and 1980, both of which included a is dominated by fall and winter floods caused number of flood peaks during the winter by dissipating tropical storms and regional months (Figure 8). The record low flow year winter storms. Webb and Betancourt point to a for this gage was 1996, in which the gage trend in meteorological phenomena, in which recorded no flow during the entire year. an increased number of dissipating tropical storms are brought into the southwestern Annual flood series. Annual flood series of the United States during ENSO (El Nino-Southern Bill Williams tributaries represent the maxi- Oscillation) conditions (Webb and Betancourt, mum peak flow volume for each year of record 1992). On the Santa Maria River, only one which have occurred during the last 50 years at large winter flood occurred between 1939 and each USGS gaging station (Figures 9-12). 1965 (3/14/41). A number of dissipating Years of extreme flooding on the rivers in the tropical storms generated floods during this study area, with record flows and multiple interval, however, including the largest flood large floods during winter months include of the gage record (8/29/51). 1978, 1980 and 1993, among others. Figure 13

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 15 Figure 7. Mean annual flow at the former USGS stream gage on the Santa Maria River near Alamo, Arizona.

Figure 8. Mean annual flow at the current USGS stream gage on the Santa Maria River near Bagdad, Arizona.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 16 Figure 9. Annual flood series for the USGS stream gage on the Big Sandy River near Wikieup, Arizona.

Figure 10. Annual flood series for the USGS stream gage on Burro Creek at Old U.S. 93 Bridge, Arizona.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 17 Figure 11. Annual flood series for the former USGS stream gage on the Santa Maria River near Alamo, Arizona. The period of record is 1939-1967.

Figure 12. Annual flood series for the USGS stream gage on the Santa Maria River near Bagdad, Arizona. The period of record is 1966-1995.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 18 Figure 13. Peak discharges during 1978, 1980, and 1993. Gages on these streams record multiple flood peaks and are the result of a series of storms during the winter months.

Figure 14. Precipitation values for the storm of February 27-March 3, 1978.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 19 displays the largest peak flows occurring for Although gages in the Bill Williams River the above years on Burro Creek, Big Sandy basin recorded large peaks for several years at River and Santa Maria River. Most of these each gage, I selected three floods that were floods appear to have been felt throughout the recorded as large-magnitude floods at more Bill Williams River basin, since stream gages than one gage in the basin, suggesting that on all three rivers typically record large flows. their effects were felt basin-wide. For the sake of brevity, only the most extreme event for each year will be discussed in the Storm of February 27-March 4, 1978. The paragraphs to follow. storm pattern for 2/27-3/4/78 follows the general scenario outlined above. The winter storm track was displaced further south than it Analysis of Selected Large Floods would normally occur and included warming Regional meteorological and hydrological data and cooling trends which delivered precipita- from storms that have impacted the Bill Will- tion during January 15-24 and February 6-16 iams River basin show similar large-scale and increased soil moisture content. Significant mechanisms and basin responses to large- antecedent moisture in the form of above magnitude precipitation events. The largest average rainfall occurred for many gages in the floods are generated from frontal and convective region. On February 27, a low-pressure trough winter storms occurring in the winter months was situated across Arizona, and brought that carry above-normal amounts of moisture showers to the Bill Williams River basin; into the southwest. In this region, precipitation moisture trailing behind a high-pressure ridge is enhanced by orographic effects from the continued the precipitation trend. On March 1, Mogollon Rim, which serves as a barrier to warm, moist air from the tropics traveling northeastward-moving moist air. The storms are northeast collided with cold air over Arizona generally characterized by anomalous and the mountain fronts of the transition zone, hydroclimatological conditions, in which a and produced the greatest precipitation of the blocking high pressure ridge creates split west- storm event for the gages in western Arizona. erly flow such that a jet stream track occurs Areas with the largest precipitation totals on further south than normal, and allows moisture March 1st include the Bagdad (3.08 in) and to be delivered to the Southwest. This track Wikieup (1.91 in) precipitation gages (Figure becomes strengthened as the trough deepens and 14). Total precipitation from February 27- may become stationary, allowing precipitation March 4, 1978 for gages in this region range to fall over the region for a number of consecu- from 3.01 in. at Prescott to 6.51 in. at Bagdad tive days. This jet stream condition may occur (Aldridge and Eychaner, 1984). Large dis- many times throughout the winter to steer charges were recorded on March 1 at stream storms over the region. Rapid warming and gages in the basin; a discharge of 36,500 cfs at cooling trends create antecedent conditions the Big Sandy River near Wikieup was the conducive to flooding as subsequent storms third largest in the gage record. A discharge of develop. Some of the antecedent conditions that 23,100 cfs recorded at the Santa Maria River have been present in the studied floods include: near Bagdad was the peak of record. Peak high soil moisture content, above average discharge in Burro Creek is unknown since the precipitation preceding the event, and high gage was not installed until 1980. water content in snow (Aldridge and Eychaner, 1984; Aldridge and Hales, 1984; Chin, et al., Storm of February 13-21, 1980. The storm of 1991; House and Hirshboeck, 1997). February 13-21, 1980 was characterized by a

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 20 series of six storms, which originated off the Arizona, increasing rainfall totals during the coast of California and moved across central winter months. Persistence of the large scale Arizona carrying warm moist air from the circulation anomaly and the repeated occur- Pacific. This event was preceded by above rence of split westerly flow also acted to average rainfall during the month of January increase precipitation above average levels, due to the southerly displaced storm track; create antecedent conditions conducive to sizable floods of 19,800 cfs at the Big Sandy flooding, and bring frontal passages through and Santa Maria stream gages occurred on the area, initiating alternating cooling and January 30,1980. The result was that the warming trends. Storms occurred during both available water holding capacity of the soil warm and cool episodes; rainfall was the was decreased by the time the February storms dominant precipitation type during warm arrived. High flows were recorded throughout events while some snowpack accumulated at the basin and were reflected in the level of higher elevations during cool events. Four Alamo Lake, which was higher than normal major storms occurred in Arizona during the due to prior flood events in 1978 and 1979 winter of 1993 that were responsible for (Chin, et al., 1991). The largest flood peak flooding in Arizona: (1) January 6-9; (2) during the storm of February 13-21 occurred January 13-19; (3) February 7-10; (4) February on February 14th at the Burro Creek gage and 18-21 (House and Hirshboeck, 1997). Al- measured 47,400 cfs. The Big Sandy and Santa though all four storms produced flood peaks in Maria gages record flood peaks of unknown the Bill Williams River basin, the storm of magnitude on February 15th and estimated at February 7-10 produced the largest peaks for 38,500 and 19,500 cfs, respectively, on the the 1993 water year and peaks of record for 20th. These peaks rank as the second largest select gages. discharges in the gage record of all three Meteorological conditions for this event tributaries. were such that moisture directed north behind a warm front was quickly followed by a cold Storm of February 7-10, 1993. The general front from the west, a scenario which provided circulation pattern during the winter of 1993 abundant precipitation for the flood event. was characterized by the development of a Precipitation ranged from approximately 60 to high-pressure area in the eastern North Pacific 80 mm with >80 mm at the highest elevations Ocean that persisted through the winter. This in the watershed. Flood peaks were produced persistent high pressure caused a branching of on February 8-9, 1993 in the Bill Williams the polar jet stream and forced the associated River basin. Burro Creek experienced its peak Pacific storm tracks further north and south of record of 55,300 cfs on February 8th at 2300 than they would normally occur. This brought hrs. Three hours later, the Big Sandy near greater cyclonic storm activity across the state Wikieup also experienced its peak of record of Arizona. Sea surface temperatures (SST’s) measuring 68,700 cfs on February 9th at 0200 remained above normal from December 1992 hrs. Santa Maria near Bagdad measured a flow through February 1993 such that warm moist of 15,700 cfs at 0300 hrs, which is the fifth air from the eastern Pacific was delivered to largest discharge on record for this site.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 21 GEOMORPHOLOGY

In order to characterize the geomorphology of these two end members, as they are confined the channels and document any changes in within canyon walls relatively close to channel channel position, I first conducted an aerial margins but are wide enough such that sedi- photo search for coverage of the Bill Williams mentation occurs along channel margins and River basin through the 20th century. Aerial secondary channels can develop. Channel photo sets that were used included sets from bedload sediments are composed mainly of 1953-54, 1963, 1972, 1976, 1978, 1980, 1985, cobbles, gravel and sand with some boulders, 1987, 1990, 1992 and 1995. Other sources of which are transported mainly during flood information include General Land Office events. Sand, silt and clay size particles make Surveys from the early 1900’s and 7.5’ USGS up the suspended load during flood events. topographic maps (Table 2). Because of the The Big Sandy River is mainly a wide and length of the three rivers and the prevalence of braided alluvial system in Big Sandy Valley canyon reaches that experience negligible with incision of less than 20 ft into higher channel change over short time periods, I terraces and alluvial surfaces when they are selected specific alluvial reaches to study in present. In its lower reaches, the river enters detail. Reach selection was based on aerial into a series of alternating confined and allu- photo reconnaissance using 1:60,000 Army vial segments. Confined reaches stretch from Map Service (AMS) photos from 1953-54 to Section 25, T15N R13W, to the north side of identify alluvial reaches which have the poten- Burro Peak and through Signal Canyon in the tial for channel change and the availability of Signal Mountain Quadrangle. photos for alluvial reaches. Reaches were then In contrast to the Big Sandy, Burro Creek mapped by aerial photo interpretation, delin- contains proportionately more confined eating active channels, terraces, and older reaches rather than alluvial reaches. Alluvial alluvium, and then comparing mapped reaches reaches that do exist are narrower and more from different years to identify channel limited in extent than those of the Big Sandy. changes. Field checking and ground photos Alluvial reaches may also contain “bottle- provide additional documentation for recent necks”, or abrupt contractions and expansions channel changes. in channel width. Alluvial reaches include: Happy Hollow Canyon to Salt Creek; Boulder Creek to Six Mile Crossing; U.S. Route 93 Channel Characterization bridge crossing; and confluence with Big The Big Sandy River, Burro Creek, and Santa Sandy River to ~1 mile above that confluence. Maria River have channel configurations that The Santa Maria River in its upper reaches range from narrow steep-walled canyons to exhibits confined narrow canyons and interme- wide alluvial reaches. Confined reaches in diate reaches that are composed of alluvial canyons typically contain a single channel and channels which narrow to bottlenecks in places. have little space for lateral channel migration. The intermediate reaches extend from Quail Alluvial reaches may also maintain a single Spring to sec 25 of T13N R9W and from Santa primary flow channel; however, secondary Maria Ranch to Black Canyon. The lower Santa channels commonly are used during large Maria River, from the gaging station to Alamo magnitude flow events. Some reaches must be Lake, is a wide alluvial reach similar to the Big characterized as an intermediate type between Sandy River in Big Sandy Valley.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 22 Table 2. List of aerial photo sources used for this geomorphologic study of the Big Sandy River, Santa Maria River and Burro Creek.

flow channel in straight reaches of the canyon Channel Change is moderately sinuous and slightly incised into The purpose of this section is to document the alluvium; around the bends the channel is wide nature and magnitude of channel changes that and shallow and supports wetland vegetation. have occurred during the 20th century. For each From its crossing with Signal Canyon road, the reach channels were delineated by aerial photo Big Sandy River returns to a wide alluvial interpretation and were designated by the channel to the confluence with Burro Creek. prevalence of channel sediment and the ab- The greatest potential for channel change lies sence of thick vegetation. Areas that contained in alluvial reaches; for this reason as well as channels with significant vegetation were not photo availability, the reach from Wikieup to designated as the main channel but instead its narrowing point serves as an illustration of were included as channel bars and overflow channel changes that have occurred on this areas within the floodplain. Some mid-channel river reach of the Big Sandy. Two subreaches vegetated bars that were between channels are will be discussed: the Wikieup reach is located not represented in order to simplify the figures. in the northern half of the Wikieup quadrangle (Figure 15) and the Hopewell Ranch reach is Big Sandy River, Burro Creek Confluence to located in the southern half of the Wikieup Wikieup. The Big Sandy River from Wikieup quadrangle (Figure 16). Data sets used in this to Burro Creek confluence is highly varied in study include General Land Office (GLO) its channel character. On the Wikieup 7 ½’ cadastral surveys and aerial photos from 1953, quadrangle, the channel is wide and braided, 1963, 1978, 1990, and 1995. but abruptly narrows as it flows south through Channel changes have been expressed a narrow canyon with tight bends. The low primarily in the form of changes in vegetation

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 23 Figure 15. Historical channel changes on the Big Sandy River, Wikieup reach.

Figure 16. Historical channel changes on the Big Sandy River, Hopewell Ranch reach.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 24 density and channel width and position, pre- The 1978 photos post-date major floods sumably in response to flood flows. GLO during the winter of 1977-1978 and reflect surveys completed in 1912 and 1917 show a changes caused by large flows. Although the channel markedly different from that of 1953 channel occupied a similar position to the and later in the historic record. In general, the channel of 1963 deposition on the Big Sandy channel delineated by GLO surveyors was River floodplain obstructed the pre-flood wide compared to later channel patterns of channel and effectively in many cases, its 1953 and 1963 and had greater sinuosity than width changed dramatically, and in some any later channel documented by aerial photos. places diverged to flow around vegetated This is especially true of the Wikieup study channel bars. In the Wikieup reach, channel reach. Although GLO survey data is less widening generally followed the 1963 channels reliable than photo documentation, channel north of Wikieup and reoccupied and accentu- positions seem reasonable by the following ated the 1953 meander near Wikieup. South of arguments: (1) The greatest bends in the Wikieup, channel changes occurred in the form channel occurred at the intersection of the of right bank erosion along agricultural fields. channel with section lines, which should Split flow existed downstream of the left bank accurately depict channel position. (2) Large erosion in which flow occupied the 1963 floods are known to have occurred in the late channel and initiated a new channel that 1800’s and early 1900’s. Because surveying diverged toward the left bank and utilized a followed this interval, it seems reasonable that road oblique to flow to widen its channel even the channel was wide and sinuous, reflecting further. The two channels rejoined approxi- the influence of large flows on channel pattern. mately ½ mile downstream from their split. In fact, according to historic accounts, the late The Hopewell Ranch reach also displays 19th century to early 20th century was a time prominent channel changes, the most spectacu- period in which many channel changes were lar of which occurred at the Bronco Creek occurring. Many homesteads that had existed confluence and downstream from the along the Big Sandy River in these reaches and confluence. On August 19, 1971, Bronco in northern Big Sandy Valley were washed Creek experienced a flood estimated at 26,000 away during the 1880’s and later. Landholdings to 30,000 cfs (House and Pearthree, 1995). that are specifically noted include: the Cornwall This flood caused major channel changes in Ranch (see Figure 16), the Boner Ranch, the Bronco Creek and deposition of fan material at Scott Place, and the town of Greenwood (Cofer, the junction of Bronco Creek and Big Sandy 1969). Channel incision of 5-10 ft and channel River. The Bronco Creek fan rerouted it toward widening in the Big Sandy River since the the left bank, narrowing the new channel. This 1860’s was also noted by Kam through written change in channel position is reflected in the communication to Davidson in 1966 (Davidson, position of the river channel in 1978 and the 1973). In 1953, multiple low-flow channels direct abutment of the Bronco Creek fan against existed within the reach and were generally this new channel. Rerouting toward the left confined to a small portion of the larger chan- bank was followed downstream by right bank nel. Photos from 1963 show an increase in cutting along the agricultural fields of the bridge vegetation in portions of active channels of terrace and erosion on the opposite bank. Down- 1953 and abandonment of a right bank meander stream of the U.S. Route 93 bridge, right bank near Wikieup in the Wikieup reach; generally, cutting occurred, eroding vegetated channel bars flow routes were very similar to that of 1953, and low terraces to bedrock. but occupied a smaller portion of the channel.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 25 Photos from 1990 capture a channel that reach; Raster Wash enters upstream of the was very similar to that of 1978 in both width bridge, while Black Canyon enters down- and position. However, the 1990 channel was stream. In contrast with the selected reaches on overall more vegetated and one channel had the other rivers, bedrock control affords less become dominant over another in areas of split potential for channel change. This is especially channel flow. For example, the eastern channel true in the vicinity of the bridge, where channel was dominant whereas the western channel position has changed minimally during the 20th was semi-vegetated. In the Hopewell Ranch century. However, around tight bends in the reach, the channel that had eroded agricultural canyon, channel widening has occurred such fields to accommodate large flow volumes was that point bars and alluvial terraces have heavily vegetated. developed. In these reaches the channel has In 1995, the channel was reduced in experienced lateral scour during floods which sinuosity and increased in width in the have repeatedly truncated Black Canyon fan Wikieup reach with noticeable erosion on the and exaggerated meander patterns on Burro outside bends of the main channel, especially Creek upstream of Raster Wash (Reach 1). along the agricultural fields on the right bank Reach 1 is the focus of the following para- in Wikieup. In the Hopewell Ranch reach, the graphs as it demonstrates the most pronounced 1995 channel was actually more sinuous than channel changes that have occurred within the that of 1978 or 1990; channel width was study site. Aerial photos used to document variable with some reaches being wider and Reach 1 were taken in 1953, 1963, 1976, 1980, some narrower than previous channel configu- 1990, and 1995. GLO surveys and topographic rations. The most noticeable channel changes maps completed in 1980 also provide informa- occurred upstream of Bronco Creek, where the tion on channel position. channel widened and migrated toward the right Reach 1 is characterized by a meandering bank, and in the vicinity of the U.S. Route 93 channel with low sinuosity issuing from a left bridge, where bank erosion is evident along the bend in upper Burro Creek (Figure 17). Two outside bends and the channel narrows as it large terraces (A; B) joined by a narrow strip flows underneath the highway bridge. The are located on right bank on the outside bend channel bends in this reach are nearly at 90 of the channel meander while smaller terraces degree angles. It is most likely that channel occupy the left bank. An overflow channel (C) differences between 1990 and 1995 aerial carved into an alcove curves along the right photos are largely a result of the floods of 1991 bank immediately upstream of Raster Wash. In and 1993. 1953, the channel was positioned centrally in Reach 1, and skirted the left bank at C. Vegeta- Burro Creek, U.S. 93 Bridge Site. Burro tion was sparse in overbank area C, indicating Creek at the U.S. 93 bridge is located in the that it must have experienced recent flow. In Kaiser Spring 7 ½’ quadrangle in T14N R11W 1963, the channel appeared very similar. By and is characterized by channel bends with 1976, however, lateral erosion had begun on point bars and minor terraces in conjunction the right bank of terraces A and B, with contin- with a narrow canyon reach below the 93 ued use of overflow area C. By 1990, the bridge. This reach is not perennial but typically channel had eroded the right bank to bedrock contains water for a good portion of the year. so that terraces A and B were no longer con- The channel itself is characterized by pools and nected. Left bank terraces downstream were riffles typical of the creek as a whole. Two also eroded, though not as dramatically. This major tributaries join Burro Creek within this effectively routed flow toward the left bank,

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 26 Figure 17. Historical channel changes on Burro Creek just upstream of the U.S. Route 93 bridge.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 27 isolating overbank area C and depositing enced a recent flood event, possibly sediment at its opening. Area C also experi- that of 1951. enced bank cutting along the edge adjacent to 1963: Channel configuration was very similar the main channel. Low relief bars decreased in to that of 1953; the low flow channel vegetation density from 1976, while vegetation along the left bank was vegetated on its in area C increased in density. Reach 1 appears margins, and additional vegetation had very similar in photos taken in 1995 with grown on bars. minimal reduction in vegetation density at the 1978: Channel configuration was very similar upper end of the reach. These changes are to 1963 photos. minimal given the fact that the 1993 flood was 1990: Channel in area A remained very the peak of record. Thus, most channel changes similar to past channel positions; occurred between 1976 and 1990, and most however, vegetation along the low flow likely resulted from the floods of 1978 and channel in area B had been partly 1980. removed and a new channel cut more abruptly from left to right; vegetation Santa Maria River, U.S. 93 Bridge Site. The continued to increase on the bridge Santa Maria River channel at the U.S. 93 terrace and terrace A. Multiple chan- bridge is an alluvial reach that issues from a nels had developed where previously more confined setting in Section 10 T12N only two could be defined R9W and reenters a confined setting down- 1995: Channel formed in 1990 was vegetated stream of the U.S. 93 bridge in Section 21 and cross cut by a new low flow chan- T12N R9W. In this reach, the Santa Maria nel down the center of the river. The River is bordered by bedrock, Pleistocene channel on the left bank in area A had terraces greater than 50 ft above the modern become a minor flow path. Bars had channel, Holocene terraces, and active gravel become more vegetated since 1990; bars. Changes have occurred in both channel however, the main channel was very position and vegetation density on terraces and clear of vegetation. In area B, split low bars; a few of these features will be used to flow channels were evident once again. highlight areas of change. These include the bridge terrace, located north of and underneath The Santa Maria River channel upstream the U.S. 93 bridge on the right bank and the from the U.S. 93 Bridge has been relatively left bank terrace in a minor alcove on the left stable during the past century, but the down- bank downstream of the bridge (Figure 18). stream reach has experienced channel migra- Site A designates the channel upstream of the tion from left to right and morphologies rang- bridge while site B represents the channel ing from braided to split flow. Changes that downstream of the bridge. Photo sets used for have occurred are reflected in differences in this analysis include 1953, 1963, 1978, 1990, channel position from 1978 to 1995. Channel and 1995. changes correspond to a time period in which large magnitude floods were recorded on this 1953: A single low flow channel was present drainage; these floods were likely responsible in area A along the left bank, and split for much of the lateral migration and erosion. in area B to form two channels which reconnected at the abrupt left bend Santa Maria River near Bagdad Gaging downstream; low relief bars were not Station to Alamo Lake. The Santa Maria vegetated and appear to have experi- River in its lower reaches is an alluvial channel

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 28 Figure 18. Historical channel changes on the Santa Maria River at U.S. Route 93 bridge.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 29 Figure 19. Historical channel changes on the Santa Maria River near Valencia Wash.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 30 Figure 20. Historical channel changes on the Santa Maria River near Date Creek.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 31 comparable in morphology and scale to allu- vegetated. By 1992, the channels upstream vial reaches of the upper Big Sandy River. hadwidened to incorporate more of the bottom- Channel widths range from less than ¼ mile at land into the primary flow path, but did not the gage near Bagdad to nearly one mile at its reach the extent of the 1953 flow pattern widest in Section 15 T11N R11W. Channel Near Date Creek, channel position differs morphology is best described as a braided markedly during the 20th century (Figure 20). system with semi-vegetated bars between In 1917, the main channel as noted by the channels. This section reviews the general surveyor was located along the right bank of channel changes that are evident in this reach the Santa Maria River. In 1953, the channel in and highlights a few areas that show dramatic the vicinity of Date Creek was composed of changes for this photo set. General channel two channels occupying the left and right changes include decreases in channel width banks. Major channel changes are evident on and increases in sinuosity from 1953 to 1976, the 1967 topographic base, where the northerly and increases in channel width and decreases channel is dominant and cuts to the left bank in sinuosity from 1987 to 1992 (Shafroth, near the mouth of Date Creek. This pattern is written communication). accentuated in 1979. By 1987, the dominant Figures 19 and 20 highlight two areas on channel upstream of Date Creek had shifted to the Santa Maria alluvial reach that have experi- a more central position; continued left bank enced changes in channel width and sinuosity. cutting shifted the channel bend downstream of The first area is located in the vicinity of Date Creek. This trend continued into 1992 Valencia Wash and demonstrates the trend in and in effect, decreased the sinuosity of this channel width (Figure 19). In the early 1900’s, reach. surveyors recorded the position of the main In summary, the most prominent channel channel as they surveyed section lines for the changes occurred from 1953 to 1979, when Township and Range grid. Along the west channel width decreased near Valencia Wash section line of sec 13 T11N R11W, the Santa and sinuosity increased near Date Creek, and Maria River was positioned in what is now a from 1979 to 1987, when the channel experi- semi-vegetated bar. By 1953, channel position enced left bank lateral erosion near Date Creek remained relatively stable near the gage but and channel widening near Valencia Wash. had shifted toward the left and right (north and The largest floods in the historic record at the south) of its previous position along the west- Bagdad gage occurred during the winters of ern border of section 13 (Figure 18). In 1953, 1978, 1980, 1991, and 1993 and seem to be the the active flow area was wide with multiple most obvious catalysts for channel change on channels transporting flow. Photos from 1979 the Santa Maria River. Generally, changes on show an overflow of sediments onto cultivated the Santa Maria River took the form of channel land on the right bank immediately down- widening, increased sinuosity, and decreased stream of the gage, and abandonment of the vegetation density in response to large floods. southernmost channel upstream of Valencia Study reaches on the Big Sandy River and Wash. In general, channels within the braided Burro Creek show similar records of channel system were diminished in size and partly change, both in the type of change and occur- vegetated when compared to those that existed rence during periods of large floods. in 1953, while the active channels were less

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 32 CONCLUSIONS

The Big Sandy River, Santa Maria River, and Big Sandy River, 53,300 cfs (2/8/93) for Burro Burro Creek flow through rugged terrain of Creek, and 23,100 cfs (3/1/78) for the Santa some of the most remote lands in Arizona. Maria River. The largest storm events resulted Although the three rivers do not have abundant in heavy, basin-wide precipitation events that water resources, they all contain perennial caused floods of varying magnitudes at all reaches along their lengths. The Big Sandy three gages. River has perennial surface water along some Substantial channel changes have oc- portions of its length and is fed by upper curred in response to large floods during the watershed perennial streams such as Trout historical period. Channel changes typically Creek. Burro Creek maintains perennial sur- have involved erosion of stream terraces and face water along most of its length, which tributary fans around outside bends, removal of during the driest intervals exists as discontinu- vegetation within the channel, and channel ous pools of standing water. The Santa Maria widening. Analysis of channel change spans is the driest of all three rivers, with most of its the 20th century; according to historic accounts, surface water supplied by tributaries in the severe channel changes occurred around the upper watershed and in the main channel for turn of the century, when large floods washed 10-15 miles near its mouth. Low flow dis- away farmlands and the old mining town of charge measurements of each river are gener- Greenwood along the Big Sandy River. The ally less than 10 cfs. Flood events are dramatic most dramatic channel changes documented by in comparison. Peak flow estimates for these aerial photo interpretation occurred from 1978 rivers are estimated at 68,700 (2/9/93) for the to 1995.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 33 REFERENCES

Aldridge, B.N., 1971, Northwestern Arizona, Floods of Carmody, T., 1980, A critical examination of the December, in southwestern United States, in ‘largest’ floods in Arizona: A study to advance the Rostvedt, J.O., and others, Summary of floods in the methodology of assessing the vulnerability of bridges United States during 1966: U.S. Geological Survey to floods for the Arizona Department of Transpor- Water-Supply Paper 1870-D, p. D62-D69. tation, General Report 1: Tucson, University of Arizona, College of Engineering, Engineering Aldridge, B.N., 1972, Investigation of floods from small Experimental Station, 53 p. drainage basins in Arizona, in Proceedings of the Twenty-first Annual Conference on Roads and Chin, E.H., Aldridge, B.N., and Longfield, R.J., 1991, Streets, held at University of Arizona, April 13-14, Floods of February 1980 in southern California and 1972: Tucson, University of Arizona, Arizona central Arizona: U.S. Geological Survey Professional Transportation and Traffic Institute, p. 107-126. Paper 1494, 126 p.

Aldridge, B.N., 1978, Unusual hydraulic phenomena of Clark, R.J., 1979, Hydrogeochemical and stream flash floods in Arizona, in Peck, E.L, ed., Conference sediment reconnaissance basic data report for the on flash floods, Hydrometeorological aspects, Los Prescott NTMS quadrangle, Arizona: U.S. Depart- Angeles, Calif., May 2-3, 1978: American Meteoro- ment of Energy Report GJBX-122(79), 92 p., 6 logical Society, p. 117-120. sheets, 7 microfiche.

Aldridge, B.N., and Eychaner, J.H., 1984, Floods of Clark, T.C., 1975, The Arizona water plan, a status October 1977 in Southern Arizona and March 1978 report, in Arizona Watershed Symposium, 19th in central Arizona: U.S. Geological Survey Water annual, Phoenix, September 24, 1975, Proceedings: Supply Paper 2223, 143 p. Arizona Water Commission Report no. 7, p. 9-23.

Aldridge, B.N., and Hales, T.A., 1984, Floods of Cofer, Irene Cornwall, 1969, The Lunch Tree: Theo. November 1978 to March 1979 in Arizona and West- Gaus Sons, Inc., Brooklyn, NY, 210 p. Central New Mexico: U.S. Geological Survey Water Supply Paper 2241, 149 p. Costa, J.E., 1978, Holocene stratigraphy in flood frequency analysis: Water Resources Research, v. 14, Anderson, T.W., 1995, Summary of the Southwest p. 626-642. alluvial basins, regional aquifer system analysis, south-central Arizona and parts of adjacent states: Davidson, E.S., 1973, Water-resources appraisal of the U.S. Geological Survey Professional Paper 1406-A, Big Sandy area, Mohave County, Arizona: Arizona p. A1-A33. Water Commission Bulletin 6, 40 p., 2 sheets, scale 1:32,000. Anderson, T.W., and Johnson, A.I., eds., 1986, Regional aquifer systems of the United States - southwest Ely, L.L., 1992, Large floods in the southwestern United alluvial basins of Arizona: Bethesda, Md., American States in relation to late-Holocene climatic variations: Water Resources Association Monograph Series no. Tucson, University of Arizona, Ph.D. dissertation, 7, 116 p. 326 p.

Baker, 1987, Paleoflood hydrology and extraordinary Enzel, Yehouda, Ely, L.L., House, P.K., Baker, V.R., flood events: Journal of Hydrology, v. 96, p. 79-99. and Webb, R.H., 1993, Paleoflood evidence for a natural upper bound to flood magnitudes in the Brown, D.E., Carmody, N.B., and Turner, R.M., 1978, Colorado River Basin: Water Resources Research, v. Drainage map of Arizona showing perennial streams 29, no. 7, p. 2287-2297. and some important wetlands, 1 sheet, scale 1:1,000,000.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 34 Evans, L.G., and Haimson, J.S., 1982, SWAB/RASA House, P.K., 1997, An unconventional, aquifer parameter study, final report for U.S. Geo- multidisciplinary approach to evaluationg the logical Survey contract 14-08-0001-18268: Arizona magnitude and frequency of flash floods in small Department of Water Resources, 21 p. desert watersheds: Arizona Geological Survey Open- File Report 97-9, 61 p. Foreman, Grant, 1941, A Pathfinder in the Southwest: The Internerary of Lieutenant A.W. Whipple during House, P.K., and Hirschboeck, K.K., 1997, his Explorations for a Railway Route from Fort Hydroclimatological and paleohydrological context Smith to Los Angeles in the Years 1853-1854: of extreme winter flooding in Arizona, 1993, in University of Oklahoma Press, Norman, 298 p. Larson, R.A., and Slosson, J.E., eds., Storm-Induced Geologic Hazards: Case Histories from the 1992- Freethey, G.W., and Anderson, T.W., 1986, 1993 Winter in southern California and Arizona: Predevelopment hydrologic conditions in the alluvial Boulder, Colorado, Geological Society of America basins of Arizona and adjacent parts of California Reviews in Engineering Geology, v. XI., p. 1-24. and New Mexico: U.S. Geological Survey Hydro- logic Investigations Atlas HA-664, 3 sheets, scale House, P.K., and Pearthree, P.A., 1994, A geomorphologic 1:500,000. and hydraulic evaluation of an extraordinary flood discharge estimate: Bronco Creek, Arizona: Arizona Garrett, J.M., and Gellenbeck, D.J., 1991, Basin Geological Survey Open-File Report 94-19, 21 p. characteristics and streamflow statistics in Arizona as of 1989: USGS Water Resources Investigations House, P.K., and Pearthree, P.A., 1994, Hydraulic and Report 91-4041, 612 p. geomorphic re-evaluation of an extraordinary flood discharge estimate: Bronco Creek, Arizona [abs.]: Gillespie, J.B., Bentley, C.B., and Kam, W., 1966, Basic Geological Society of America Abstracts with hydrologic data of the Hualapai, Programs, v. 26, no. 7, p. A.235-A.236.

Graf, J.B., Webb, R.H., and Hereford, Richard, 1991, House, P.K., and Pearthree, P.A., 1995, A geomorphologic Relation of sediment load and flood-plain informa- and hydraulic evaluation of an extraordinary flood tion to climatic variability, Paria River drainage discharge estimate: Bronco Creek, Arizona: Water basin, Utah and Arizona: Geological Society of Resources Research, v. 31, no. 12, p. 3059-3073. America Bulletin, v. 103, p. 1405-1415. House, P.K., Pearthree, P.A., and Wood, M.L., 1999, Grimm, N.B., and Fisher, S.G., 1986, Nitrogen limitation Hydrologic and geomorphic characteristics of the Bill potential of Arizona streams and rivers: Arizona- Williams River, Arizona: Arizona Geological Survey Nevada Academy of Science, Journal, v. 21, p. 31-43. Open-File Report 99-4, 47 p., 2 sheets, scale 1:24,000.

Halpenny, L.C., and others, 1952, Ground water in the Gila Johnson, M.G., 1972, Placer gold deposits of Arizona: River basin and adjacent areas, Arizona—a summary: U.S. Geological Survey Bulletin 1355, 103 p., 1 sheet. U.S. Geological Survey Open-File Report, 224 p. Kochel, R.C., and Baker, V.R., 1982, Paleoflood Hereford, Richard, Thompson, K.S., Burke, K.J., and hydrology: Science, v. 215, p. 353-376. Fairley, H.C., 1996, Tributary debris fans and the late Holocene alluvial chronology of the Colorado River, Macklin, M.G., Rumsby, B.T., and Newson, M.D., eastern Grand Canyon, Arizona: Geological Society 1992, Historical floods and vertical accretion of fine- of America Bulletin, v. 108, no. 1, p. 3-19. grained alluvium in the Lower Tyne Valley, North- east England, in Billi, P., Hey, R.D., Thorne, C.D., House, P.K., 1993, The Arizona floods of January and and Tacconi, P., Dynamics of Gravel BedRivers: February 1993: Arizona Geology [Arizona Geologi- New York, John Wiley and Sons Ltd., p. 573-589. cal Survey], v. 23, no. 2, p. 1, 6-9. Markman, S.G., 1996, Assessmemt of water resource conditions in support of instream flow water rights, Burro Creek, Arizona: U.S. Bureau of Land Manage- ment, 25 p.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 35 Melton, M.A., 1965, The geomorphic and paleoclimatic Texas Instruments, Inc., 1982, National uranium significance of alluvial deposits in southern Arizona: resource evaluation, variable premise evaluation Journal of Geology, v. 73, no. 1, p. 1-38. system data report, interpretation of hydrogeochemical and stream sediment reconnais- Menges, C.M., and Pearthree, P.A., 1989, Late Cenezoic sance data, Williams quadrangle, Arizona: U.S. tectonism in Arizona and its impact on regional Department of Energy Report GJD-93(81), 264 p. landscape evolution, in Jenney, J.P., and Reynolds, S.J., 1989, Geologic evolution of Arizona: Tucson, Tucci, Patrick, 1989, Geophysical methods for water- Arizona Geological Society Digest 17, p. 649-680. resources studies in southern and central Arizona, in Symposium on the Application of Geophysics to Patton, P.C., Baker, V.R., and Kochel, R.C., 1979, Engineering and Environmental Problems, Proceed- Slackwater deposits: a geomorphic technique for the ings: Denver, Society of Engineering and Mineral interpretation of fluvial paleohydrology, in Rhodes, Exploration Geophysicists, p. 368-383 [available for D.P., and G.P. Williams, eds., Adjustments of the inspection at Arizona Geological Survey, 416 W. Fluvial System: Dubuque, Iowa, Kendall/Hunt, p. Congress, Suite 100, Tucson, Ariz.]. 225-253. United States Army, Office of the Chief Engineer, 1944, Richmond, D.L., and Richardson, M.L., 1974, General Bill Williams River and Tributaries, Arizona, soil map and interpretations, Mohave County, Washington, D.C.: Government Printing Office, 78th Arizona: U.S. Department of Agriculture, Soil Congress, 2d Session, House Document No. 625. Conservation Service, 48 p., 1 sheet, scale 1:600,000. United States Bureau of Land Management, 1990, Robertson, F.N., and Garrett, W.B., 1988, Distribution Kingman Resource Area, Resource management plan of fluoride in ground water in the alluvial basins of and environmental impact statement - Draft: U.S. Arizona and adjacent parts of California, Nevada, Bureau of Land Management, 282 p., 8 sheets, scales and New Mexico: U.S. Geological Survey Hydro- 1:168,960 and 1:320,000 [BLM-AZ-PT-90-012-1600]. logic Investigations Atlas HA-665, 3 sheets, scale 1:500,000. United States Bureau of Land Management, 1993, Kingman Resource Area, Proposed resource manage- Sacramento, and Big Sandy Valleys, Mohave County, ment plan and final environmental impact statement: Arizona: Arizona State Land Department Water U.S. Bureau of Land Management, 606 p. [BLM/AZ/ Resources Report no. 26, 39 p. PL-93/009-4410].

Sellers, W.D., and Hill, R.H., 1974, Arizona Climate, Wagoner, J.L., 1979, Hydrogeochemical and stream 1931-1972, Tucson, Arizona, The University of sediment reconnaissance basic data report for Arizona Press, 616 p. Williams NTMS quadrangle, Arizona: U.S. Depart- ment of Energy Report GJBX-71(79), 74 p., 6 sheets, Spencer, J.E., and Reynolds, S.J., 1989, Middle Tertiary scale 1:250,000, 5 microfiche. tectonics of Arizona and adjacent areas, in Jenney, J.P., and Reynolds, S.J., 1989, Geologic evolution of Webb, R.H., and Betancourt, J.L., 1992, Climatic Arizona: Tucson, Arizona Geological Society Digest variability and flood frequency of the Santa Cruz 17, p. 649-680. River, Pima County, Arizona: U.S. Geological Survey Water-Supply Paper 2379, 40 p. Stedinger, J.R., and Cohn, T.A., 1986, Flood frequency analysis with historical and paleoflood information: Wendt, G.E., 1972, General soil map, Yavapai County, Water Resources Research, v. 22, p. 785-793. Arizona; original text and map by G.E. Wendt, 1968- 69; text and mapping legend revised and interpreta- Tellier, A.H., 1973, Geothermal waters of Arizona: tions added April 1972 by M. L. Richardson: U.S. Tempe, Arizona State University, M.S. thesis, 30 p. Department of Agriculture, Soil Conservation Service, 46 p., 1 sheet, scale 1:500,000.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 36 Wendt, G.E., Winkelaar, P., Wiesner, C.W., Wheeler, Wolcott, H.N., Skibitzke, H.E., and Halpenny, L.C., L.D., Meurisse, R.T., Leven, A., and Anderson, T.C., 1956, Water resources of Bill Williams River Valley 1976, Soil survey of Yavapai County, Arizona, near Alamo, Arizona, in Contributions to the hydrol- western part: U.S. Department of Agriculture, Soil ogy of the United States: U.S. Geological Survey Conservation Service, 121 p., 176 sheets, scales Water-Supply Paper 1360-D, p. 291-319, 1 sheet, 1:31,680 and 1:570,240 [errata: symbols on original scale 1:64,000. General Soil Map are incorrect]. Wright, J.J., 1971, The occurrence of thermal ground-water Wilson, L.G., DeCook, K.J., and Neuman, S.P., 1980, in the Basin and Range Province of Arizona, in Evans, Regional recharge research for southwest alluvial D.D., ed., Hydrology and water resources in Arizona basins - final report, U.S. Geological Survey contract and the Southwest, v. 1: American Water Resources 14-08-0001-18257: Tucson, University of Arizona, Association, Arizona Section, and Arizona Academy of Water Resources Research Center, 389 p. Science, Hydrology Section, Annual Meeting, Tempe, Ariz., 1971, Proceedings, p. 269-290.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 37 APPENDIX A

Stage-discharge rating curves for USGS stream gages

Figure A1. Composite rating curve for the Big Sandy River near Wikieup, Arizona.

Figure A2. Rating curve for Burro Creek at Old US 93 Bridge, Arizona. rating table 4; start date (time): 9-30-90 (2400)

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 38 Figure A3. Rating curve for Santa Maria River near Bagdad, Arizona. rating table 4; start date/time: 9/30/90 (2400)

Figure A4. Rating curve for Francis Creek near Bagdad, Arizona. rating table 5; start date (time): 10-01-92 (0001)

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 39 APPENDIX B

Photo documentation of river reaches

Photographs in this appendix are not a comprehensive set that document river morphology but rather provide a glimpse of selected reaches for each river. The Big Sandy River and Burro Creek photo sets also contain comparative photos, the first photo most likely taken in the early 1960’s and the second in 1998. A photo index describes the location and characteristics for each photo in the following paragraphs.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 40 Figure B1. Big Sandy River at U.S. Route 93 Bridge—photo comparison: looking upstream Location: SW ¼ SW ¼ sec 1 T15N R13W

A historical photo (top) taken by Carlos Elmer1, who was active in Mohave County between 1948 and 1975, depicts an autumn flood on the Big Sandy. The lower photo taken in 1998 by J.Klawon illustrates channel morphology of the Big Sandy in low flow conditions. During periods of low flow, the Big Sandy occupies a narrow semi-entrenched channel and is bounded by an extensive floodplain of fine sediments and full-grown trees outside of what is presumably the high flow channel. Extreme events occupy a greater portion of the floodplain; in the Elmer photo, floodwaters are seen inundated even well vegetated portions of the floodplain and dis- lodging some of this debris to carry downstream.

1 Carlos Elmer, “Big Sandy River in flood nr. Wikieup.” CP Photographs Collection, Arizona Collection (CP SPC 214A: 4462). Dept. of Archives and Manuscripts, University Libraries, Arizona State University, Tempe.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 41 Figure B2. Big Sandy River downstream of Trout Creek Location: NE ¼ sec 35 T18N R13W

Sandy and gravelly wide alluvial channel with low mid-channel terraces infrequently inundated.

Figure B3. Big Sandy River near Signal Location: NW ¼ SE ¼ sec 25 T15N R13W

Entrenched moderately sinuous channel of fine-grained sediment with abundant vegetation along channel margins and filling the channel in some locations.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 42 Figure B4. Burro Creek high bridge—photo comparison: looking upstream Location: NW ¼ SW ¼ sec 19 T14N R11W

The high bridge over Burro Creek on U.S. Route 93 was completed sometime between 1963 and 1976. The photograph on the top by Carlos Elmer was most likely that the photo was taken soon after the bridge’s completion; The high flow event shown in this photo narrows the probably dates to August or September of 1963, 64 or 71. The photo on the right was taken in the fall of 1998 by J. Klawon. Comparison between the two photos demonstrates the differences and similarities between high flow and low flow channel patterns. Floodwater occupies 2 channels in the foreground of Elmer’s photo, with the channel along the right bank as the main channel and the channel along the left bank as an overflow channel with a noninundated bar separating the two. Channel configuration in 1998 is very similar with the low flow channel hugging the right bank and a vegetated channel bar on the left. Much of the existing vegetation along the left bank is inundated by the floodwaters of the Elmer photo; generally there is less vegetation in the channel than that of 1998 (note the absence of species on the downstream gravel bar on the left bank). The early photo may have been taken in the waning stages of this particular flood, shown by the evidence of recent flow on the gravel bar to the far right on the photo.

2 Carlos Elmer, “Low Bridge at Burro Creek.” CP Photographs Collection (CP SPC 214A: 2958). Dept. of Archives and Manuscripts, University Libraries, Arizona State University, Tempe.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 43 Figure B5. Burro Creek low bridge—photo comparison: looking downstream Location: NW ¼ SW ¼ sec 19 T14N R11W

The low bridge at Burro Creek was in use as the primary traffic route over Burro Creek for U.S. Route 93 until the completion of the high bridge. After this, the low bridge continued to be maintained and in 1980, a USGS stream gage was installed on its downstream side. Note that this gage can be seen in the 1998 (bottom) photo but not in Elmer’s (top) photo2. Possible dates for this photo range from 1948 to 1975; the truck on the bridge appears to be a make and model from the early 1960’s (Ferguson, personal communication). Although channel position in both photos is very similar, vegetation density had decreased from the Elmer’s photo to 1998. Major differ- ences in vegetation occurred in the main channel downstream of the low bridge, and on the left bank low terrace upstream of the bridge.

3 Carlos Elmer, “Low Bridge at Burro Creek.” CP Photographs Collection (CP SPC 214A: 2958). Dept. of Archives and Manuscripts, University Libraries, Arizona State University, Tempe.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 44 Figure B7. Santa Maria River near U.S. Route 93 bridge Location: NW ¼ NE ¼ sec 22 T12N R9W

This photo was taken looking west-northwest (upstream) from a high Pleistocene terrace on the left bank. The river bends from right to left on the photo around the low terrace of Santa Maria Ranch and turns sharply to the southwest off the bottom of the photo. In this reach, the river channel is composed mainly of sand and gravel with vegetation along channel margins and low terraces. The low flow channel occupied the outside bend of the river in this photo.

Figure B6. Burro Creek near Big Sandy River confluence Location: sec 19 T12N R9W

Sandy and gravelly wide alluvial channel with low fine-grained to gravelly Holocene terraces (center of photo) and higher Pleistocene terraces (banks on sides of photo).

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 45 Figure B8. Santa Maria River near Bagdad, AZ Location: SE ¼ SE ¼ sec 12 T11N R11W

The Santa Maria River channel issues from the upstream reach of intermediate width to a wide alluvial braided channel of mainly sands and gravels. The gaging station for the Santa Maria is situated on the bedrock protrusion to the left of the photo. Although it is not evident in this particular photograph, most portions of the alluvial reach from the gage to Alamo Lake contain relatively stable vegetated channel bars.

Hydrology and Geomorphology of the Santa Maria and Big Sandy Rivers and Burro Creek, Western Arizona by Jeanne E. Klawon Page 46